"They're probably OK," says Chuck Gerba, University of Arizona Professor of microbiology, father to two and grandfather to two. He worries more about shared toys at daycare and on playdates.

What you can do: Wash hands during (and definitely after) playdates but also recognize some of this is out of your control. After all, Gerba points out that "kids under age two put something in their mouths about 81 times per hour. Under five, they do it 50 times an hour." So, chances are, at some point they're going to pick up a playmate's stomach bug. All you can really do to curb infection is keep your child home when he's sick.

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True or False: Grocery carts are germ-infested

True

Gerba has tested grocery carts in some areas of the country and found that "80% had E. coli on them." And it's no wonder: kids poop while they're riding in them, raw meat gets tossed in, and manure-exposed produce from farms fills them. Gerba has also discovered a new area of grocery contamination: the self-service check out counters. "We've found all kinds of fecal bacteria and even MRSA (a dangerous antibiotic-resistant bacteria) on them," he says. "Apparently no one's cleaning them."

What you can do: Gerba whips out the antibacterial wipes as soon as he enters the store and recommends travelling with your own in case your store doesn't offer them. Wipe down the cart seat and handles (basically, anywhere your kids may touch or -- yuck! --lick). You can also purchase a cart cover that will minimize kid-cart contact. Put all your produce in plastic bags and double-bag your meat products. And don't let your kids "help" at the self-service counters.

True or False: Baby wipes clean hands after a diaper change

False

Washing with good old soap and water effectively eliminates germs through friction and running water. A quick swipe with a baby wipe is not nearly as effective, says Shu.

What you can do: If you're away from a sink, she recommends putting a little elbow grease into your wiping or use an alcohol-based hand sanitizer.

True or False: Kids in daycare are healthier as they grow older, thanks to early exposure to a lot of different bugs

The jury's out

"The answer is not completely clear," says Mimi Glode, MD, head of pediatric infectious disease at the Children¿s Hospital in Denver, Colorado. A theory called the hygiene hypothesis posits that increasing asthma rates can be blamed, in part, on over- cleaning. "It's still being studied," says Glode who followed children entering kindergarten for six months and recorded how often they missed school for illnesses. Then she looked at what kind of childcare the children had for their first five years of life. "Our theory was that the daycare kids would be healthier, says Glode, "but there was no difference in the groups. I think there are enough viruses out there ready to get you, and I'm not convinced that exposing kids earlier and thinking they will be healthier is going to work out." Adds Shu, "There's no recommendation that says putting your kids in daycare is better."

What you can do: Choose whatever childcare situation is best for your family. "It's not an issue that should determine how you raise your kids," says Shu.

While it's true that your breastmilk will eventually contain antibodies to the bug you've got and those will help protect your child in the long run, it takes awhile for those antibodies to develop, says Glode. In the meantime, you're holding your child close during breastfeeding and exposing him to your germs, and since "most common viruses, have a short incubation period," there's a chance he will get sick.

What you can do: Don't worry about it and keep snuggling. There's no way to avoid a lot of mom-baby contact when you've got a little one (and who would want to?).

True or False: Dishwashers sanitize bottles and sippy cups

True

"The drying cycle reduces bacteria by at least 99.9%," says Gerba.

What to do: Gerba recommends washing and drying on the hot setting to really get those bottles and sippies clean. If you don't have a machine at home, let kiddie products air dry. That will keep them cleaner than drying with dishtowels, which "tend to distribute microorganisms, because they get a lot of food debris on them."

True or False: Cold water washes clothes as well as hot

False

"You really do need hot water," says Gerba. "Rotoviruses are very resistant to cold water washing." According to Gerba, only 5% of the American people use hot water, which contributes to the growing numbers of germs we're exposed to. Here's a fun piece of trivia with which to gross out your friends: "Adults have a tenth of a gram of poop in their underwear. When you wash 10 pairs, you have a tablespoon of poop in your washing machine." Convinced?

What you can do: Use the hot water wash every time, and dry clothes for at least 45 minutes.

True or False: You don't need to wash organic fruit

False

Organic may mean it's grown without pesticide, but it still needs to be washed, says Gerba, who adds that 80% of food-borne illnesses occur in the home.

What you can do: Scrub all fruits and vegetables. If you have small children, Gerba recommends using a bleach solution (one tablespoon of bleach to a gallon of water), a bleach alternative such as hydrogen peroxide, or special fruit-and-veggie wash.

True or False: The 5-second rule

False

This is one of those self-delusions that's useful when the last pretzel that was keeping your kid busy falls on the floor, but has no basis in fact. In fact, in 2007, scientists at Clemson University put it to the test and found that bacteria can be transferred from tabletops and the floor to dropped food in under five seconds. (Although they also found that the longer the food sits there, the greater the number of bacteria that colonize it.)

What you can do: If you want to use that last fact to rationalize popping that morsel of muffin that just hit the floor back in your mouth, feel free, but the fact is that even a quick drop on the floor can expose you to illness-causing bacteria. Better to just pitch it.

True or False: Kids have to be washed every night

False

Here's something you can take off your daily to-do list. "They need to be washed once or twice a week, depending on how dirty they are," says Shu. "My son, who is a nine-year-old baseball player, needs to be washed every day. But a four-month-old who can't move doesn't need it."

What to do: Shu says, "you want to spot clean the areas that are obviously dirty -- the hands, face, neck (for drooling babies and messy eaters), and the genitals, which should get daily wipe-downs till potty training."